This invention relates generally to the field of orthopedic medicine and more specifically to the design of an improved medical bandaging product and material that includes a fabric substrate impregnated with a moisture-curable resin, a method for constructing such an improved bandaging product, and a method of constructing and applying an improved bandaging product. More particularly, the present invention relates to an orthopedic cast tape formed from a resin-coated fabric substrate featuring a unique combination of non-fiberglass high and low tenacity yarns.
Conventional moisture-curable bandages incorporate substrates impregnated with plaster-of-paris or formed from flexible fiberglass fabric layers impregnated with a moisture-curable resin. Bandages formed from these materials possess several disadvantages. In particular, casts formed using plaster-of-paris bandages have a relatively low strength to weight ratio. This results in a finished cast that is very heavy and bulky. Furthermore, plaster-of-paris splints are slow to harden, requiring 24 to 72 hours to reach maximum strength. Because plaster-of-paris breaks down in water, bathing and showering are difficult. Even if wetting due to these causes can be avoided, perspiration over an extended period of time can break down the plaster-of-paris and create a significant problem with odor and itching.
Although medical bandages utilizing moisture-curable substrates formed from fiberglass fabric layers are lighter, waterproof and permeable to X-rays, cured casts made using such bandages can become brittle, break down during wear and often need to be replaced. Furthermore, fiberglass is a composition that is highly irritating to mammalian skin. When fiberglass casts are removed, irritating dust or fibers are often generated and become embedded in the skin of the patient.
This invention overcomes the disadvantages of prior art fiberglass substrates by providing a medical bandage formed from a resin-impregnated substrate formed from a knitted fabric that incorporates low modulus, inelastic and elastic fibers. The unique substrate of the present invention results in a bandage that exhibits good conformability compared to prior art fiberglass substrates, possesses sufficient rigidity when cured, and shows no loss of strength compared to casts formed from fiberglass substrates. This novel substrate is less brittle and more durable than prior art fiberglass substrates when cured, and does not disintegrate into irritating dust and/or fibers when removed from the injured body part of a patient.
As used herein, the terms “fiber” and “yarn”, whether appearing in singular or plural form, are used interchangeably and refer to the material that is used to form the substrate of the present invention, regardless of whether that yarn or fiber is formed of monofilament or multifilament fibers.